The present invention relates to devices that dispense air treatment chemicals from a substrate mounted above a candle flame. More particularly, the invention relates to structures associated with such devices for rendering them more suitable for controlling flying insects outdoors.
A variety of devices are known for dispensing volatilizable air treatment chemicals such as pest control materials (e.g., insecticides, insect repellants, or insect growth control regulators), air scents or deodorizers (e.g. masks), allergen control ingredients, disinfectants, sanitizers or other materials. In some of these devices the air treatment chemical is mixed with candle wax and is dispensed during a candle burning process (where the chemical is released primarily from the heated wax surrounding the wick). While this is a common technique for dispensing a variety of fragrances, and even some materials such as citronella that have some insect control capability, typically it has been less successful when dispensing certain particularly desirable pest control materials.
There have been attempts to improve efficiency by placing some structures over the candle. However, most of these devices were focused on improving candle burning efficiency in a deep-cup type candle, rather than distributing air treatment chemicals from sources other than the wax.
Other attempts have been made to use the heat from a candle (or other heat source) to distribute air treatment chemicals from an adjacent impregnated pad or the like. See e.g. U.S. Pat. Nos. 2,742,342, 4,781,895, 6,482,365, 6,503,459, and 7,138,130. However, these devices required relatively expensive constructions to achieve their results, or suffered inefficiencies, or were not be optimally suited for use outdoors.
One particularly desirable type of candle dispenser was disclosed in U.S. Pat. No. 8,047,837. There, a candle heated a chimney form of heating plate that was supported over the candle. A washer shaped impregnated substrate was positioned on the plate around the chimney and dispensed active when heated air passed through the chimney, warmed the plate, and thereby warm the substrate. However, the dispensing characteristics of this candle were not optimally controlled.
Thus, a need continues to exist for improved candle dispenser assemblies, particularly where the dispenser is primarily intended for outdoor use.